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Show 68 ZOOLOGY OF TilE VOYAGE OF THE BEAGLE. 1 have termed this species signata, in reference to the black patch on the opercle, which is a conspicuous character. The only specimen in the collec~ion was obtained by Mr. Darwin at Bahia Blanca, on the coast of North Patagoma. 1. CARANX DECLIVIS. Jen. PLATE XIV. C. corpore elongato, altitudine quintam, capite quartam part em longitudinis (IJquante; maxilla inferiore longim·e ; lined laterali infra quintum 1·adium dorsalis secund(IJ subito declitJi, per totam longitudinem armatd, laminis 82 altioribus quam longis, ubique (l!qualibus; spina reclinatd ante pinnam dorsalem parva, mucrone tamen nudato ,· pectoralibus ultra pinnulam analem, et prope ad analem ipsam, pertingentibus. B. 7; D. 8-1/35; A. 2-IJ30; C. 17, &c.; P. 21; V. 1f5. LoNG. unc. 7. lin. 10. FonM.-Rather more elongated than the C. trachurUfl of the British seas. Greatest depth one-fifth of the entire length: head one-fourth of the same: thickness about half the depth. Diameter of the eyes a little less than one-third the length of the head. Lateral line bending downwards more suddenly, and at a more backward point than in that species. The bend commences in a line with the fifth ray of the second dorsal, and is entirely comprised within a space equal to that occupied by four fin rays,• so that opposite the ninth ray it again advances in a horizontal line. The posterior portion about equals in length the anterior, the bend being included in this last. The laminre which protect the lateral line, and which extend throughout its whole length, are well developed, and everywhere of the same breadth; this breadth equalling nearly, but not quite, one-third the depth of the body. In number they are eighty-one or eighty-two; of which the last thirty-eight or forty, forming the posterior portion of the line, have keels terminating backwards in sharp spiues : these spines are at first small and inconspicuous, but gradually increase in size as they advance towards the thinnest part of the tail, where they are sharpest and most developed. In most of its other charactel's this species so closely resembles the C. trachurus, as to render a detailed description unnecessary. The reclined spine before the first dorsal, however, is smaller, though the point is sharp and exposed : also the number of rays in the second dorsal and anal is greater by five in each fin. The length of the second dorsal is two-and-ahalf times that of the first. The pectorals are long, narrow, and pointed; a little shorter than the head, or rather Jess than one-fourth of the entire length ; when laid back, they reach beyond the anal fin let, and very nearly to the commencement of the true anal itself. CoLOua.-Not noticed in the recent state. So far as can be judged from a specimen in spirits, the colours appear to have been similar to those of the C. tracllUrus; and there is the same black spot on the upper part of the opercle. • In the C. traclwrus, the bend begins in a line with the commencement of the second dorsal, and from its more gmdual obliquity, extends over a space equal to that occupied by nine fin-rays. |